RNA干扰的机制及其应用

RNA干扰(RNA interference,RNAi)是真核生物中高度保守的,由小分子干扰RNA(small interfering RNA,si RNA)介导的转录后基因沉默现象,在基因功能的研究中得到了非常广泛的应用,并有望成为小核酸药物在疾病治疗中发挥重要作用。现对近年来RNAi的作用机制、si RNA的产生途径、引起RNAi副作用的原因以及RNAi表达载体的设计这四个方面的国内外研究进展进行了总结,对RNAi与CRISPR技术在应用中的关系进行了探讨,展望了RNAi技术未来的发展。     

RNA干扰用于基因治疗的研究进展

RNA干扰(RNAi)是20世纪末才被人们认识和重视的一种通过双链RNA抵御病毒入侵或抑制转座子活动的生物防御机制。随着RNA干扰分子机制研究的深入及其应用研究的发展,人们发现RNA干扰技术在基因功能研究及人类疾病的基因治疗上具有广阔的应用前景。本文在简述RNAi分子机制的基础上,综述了RNAi在抗病毒治疗及抗肿瘤治疗方面的研究和应用概况。     

RNA干扰技术在哺乳动物中的应用

RNA干扰(RNAi)是生物界普遍存在的一种抵御外来基因和病毒感染的进化保守机制.RNAi是由双链RNA触发的转录后基因沉默机制,具有序列特异性,在哺乳动物细胞中,RNAi由21～23个核苷酸组成的双链RNA引发.小干扰RNA(siRNA)可以在体外合成或通过表达载体在哺乳动物细胞内合成.由于RNAi技术具有快速、简单和特异性强等特点,在基因功能研究、抗病毒治疗和抗肿瘤治疗等方面有广泛的应用前景.     

基因枪在RNA干扰中的应用研究进展

RNA干扰（RNA interference,RNAi）是指双链RNA（double-strand RNA,dsRNA）特异性降解同源mRNA,从而引发基因转录后水平沉默的现象,是一种高效、高特异性抑制基因表达的途径。自1998年Fire等发现RNA干扰现象以来,其特异性降解目的基因的优势吸引了众多研究者的目光。本文在简要综述RNAi技术在基因功能研究、抗病毒治疗,肿瘤基因治疗等领域的应用后,重点归纳了基因枪技术在RNAi研究即siRNA导入细胞中的应用,并简单分析其优势与意义。     

RNA干扰药物用于疾病治疗的安全性问题

RNA干扰（RNA interference,RNAi）是指由双链RNA介导的序列特异的转录后基因沉默。RNAi技术因其特异性、高效性而备受青睐,在疾病治疗方面表现出广阔的应用前景。然而,近年来的研究发现,基于RNAi技术开发的药物存在安全性问题,主要包括引起免疫反应、产生脱靶效应、以及存在竞争微RNA通路等。这些问题的突破将使RNAi技术获得更加广泛的应用。     

RNA干扰药物用于疾病治疗的安全性问题

RNA干扰(RNA interference,RNAi)是指由双链RNA介导的序列特异的转录后基因沉默.RNAi技术因其特异性.高效性而备受青睐,在疾病治疗方面表现出广阔的应用前景.然而,近年来的研究发现,基于RNAi技术开发的药物存在安全性问题,主要包括引起免疫反应,产生脱靶效应、以及存在竞争微RNA通路等.这些问题的突破将使RNAi技术获得更加广泛的应用.     

RNAi在抗病毒防治领域的应用

RNAi是由双链RNA(dsRNA)所诱发的转录后水平上的基因沉默.由于对靶基因沉默作用的高度特异性和高效性,因此近年来用于肿瘤性疾病、感染性疾病、遗传性疾病等疾病的基因治疗研究,特别是在抗病毒领域的研究更是成为其应用热点之一.虽然目前RNAi已经较为广泛地应用于动物病毒及各种疾病病毒的基因治疗研究中,但其在应用过程中还有许多亟待解决的问题.本文就RNAi及其在抗病毒领域的应用研究和其存在的问题展开综述.     

RNAi抗病毒感染的研究进展

RNAi是双链RNA在细胞内诱导产生的转录后基因沉默现象。它广泛存在于多种生物体内,是宿主细胞防御微生物感染的进化机制。近年来,RNAi的研究日渐深入,尤其是RNAi的抗病毒作用倍受关注,其研究也取得了显著成绩。本文概述了RNAi的抗病毒机制以及RNAi在抗病毒感染中的应用等方面的研究进展。     

RNA干扰技术在水产动物抗病毒和抗寄生虫研究中的应用研究进展

RNA干扰(RNA interference,RNAi)是由双链RNA介导的,抑制目标基因的表达,沉默靶基因的一种转录后基因沉默机制,并且在真核生物中广泛存在。近年来随着水产养殖业的发展壮大,水产动物疾病频繁爆发,给养殖户带来巨大的经济损失。目前,病毒、寄生虫等病原引起的水产动物疾病的致病机制还有待深入研究。RNA干扰技术的出现为水产动物疾病致病机制的研究提供了强有力的工具。主要对RNA干扰的发现、作用机制以及在水产动物抗病毒和抗寄生虫研究中的应用作以综述,并对未来RNAi技术在水产动物疾病防治中的研究和应用进行了展望,旨为水产动物疾病控制提供参考。     

慢病毒载体介导RNAi的研究进展

RNAi通过双链RNA的介导,特异性阻抑相关序列的表达,从而导致转录后水平的基因沉默.广泛存在于真菌、植物和动物等真核生物中.慢病毒载体是理想的真核细胞基因转移工具,被广泛应用于相关的RNAi研究领域,例如抗病毒研究、癌症及其治疗、遗传性疾病的治疗、基因治疗.现已发现,慢病毒载体能够介导组织特异、时间特异的RNAi,在疾病的基因靶向性治疗上必有广阔的前景.     

RNAi及其在家禽病毒病治疗上的应用

双链小RNA介导的RNA干扰(RNA interference,RNAi)是近年发现的一项以序列特异方式诱导同源mRNA降解的新技术。由于RNAi精巧的特异性和有效性,已被认为是特异性基因治疗的重要工具。其中作为抑制病毒复制的潜在工具更为引人注目。因此,将RNAi的作用机制和其在家禽病毒病治疗上的应用做以综述。     

Biochemical mechanisms of suppression of RNA interference by plant viruses

RNA interference (RNAi) plays an important biological role in regulation of gene expression of eukaryotes. In addition, RNAi was shown to be an adaptive protective molecular immune mechanism against viral diseases. Antiviral RNAi initiates from generation of short interfering RNAs used in the subsequent recognition and degradation of the viral RNA molecules. As a response to protective reaction of plants, most of the viruses encode specific proteins able to counteract RNAi. This process is known as RNAi suppression. Viral suppressors act on various stages of RNAi and have biochemical properties that enable viruses to effectively counteract the protective system of plants. Modern molecular and biochemical investigations of a number of viral suppressors have significantly expanded our understanding of the complexity of the nature of RNAi suppression as well as mechanisms of interaction between viruses and plants.     

Anti-coxsackieviral efficacy of RNA interference is highly dependent on genomic target selection and emergence of escape mutants

Enteroviral diseases are widespread and impose significant importance in medicine. Although the outcome of diseases that are associated with enteroviruses such as myocarditis, pancreatitis, hepatitis, or encephalomyelitis might be fatal, no specific antiviral therapy is yet available. We and others have shown that RNA interference (RNAi) effectively limits picornaviral replication and cytopathogenicity and improves survival in susceptible mice. However, little is known about the dependence of short interfering RNA (siRNA) efficacy on target region selection and emergence of viral escape mutants that may limit the effect of RNAi. The results of our study indicate that antiviral siRNA should be targeted preferentially to nonstructural protein coding regions because siRNA efficacy was consistently found to be superior compared to noncoding or structural protein coding regions. Further more, emergence of viral escape mutants that harbor single point mutations in the central part of the siRNA binding motif are the major factor that limits early therapeutic siRNA efficacy. The appearance of viral escape mutants can be sufficiently suppressed by combined administration of at least three distinct siRNA molecules. Therefore, genomic target selection and viral escape mutants are the most critical factors that limit early RNAi directed against enteroviral genomes. Both obstacles can be circumvented by appropriate target selection and combined siRNA administration.     

RNA干扰在疾病治疗方面的应用研究

RNA干扰是由双链RNA引起的序列特异的基因沉默现象。由于RNA干扰能在细胞组织及动物模型中沉默疾病相关基因,因此,RNA干扰也是各种疾病治疗的有效手段。在哺乳动物细胞内诱导RNA干扰可以通过导入小干扰RNA（siRNA）,或是以质粒、病毒为载体表达短的发夹RNA（shRNA）而实现。本文介绍了RNA干扰在疾病治疗方面的应用,并就其面临的挑战进行讨论。     

Efficient regulation of viral replication by siRNA in a non-human primate surrogate model for hepatitis C

RNA interference (RNAi) represents a new technology which could offer potential applications for the therapeutics of human diseases. RNAi-mediated therapy has recently been shown to be effective toward infectious diseases in in vitro and rodent models, however, it remains unclear whether RNAi therapy with systemic application could be effective in primates. In this study, we examined if RNAi therapy could be effective toward infectious diseases by using a non-human primate surrogate model for hepatitis C. Administration into marmosets of cationic liposome-encapsulated siRNA (CL-siRNA) for GB virus B (GBV-B), which is most closely related to hepatitis C virus, repressed GBV-B replication in a dose-dependent manner. Especially, 5 mg/kg of the CL-siRNA completely inhibited the viral replication. Since the serum interferons (IFNs) were induced by CL-siRNA in vivo, inhibition of viral regulation by anti-GBV-B CL-siRNA may include an antiviral effect of IFN. However, contribution of induced IFN may be partial, since the control CL-siRNA which induced a stronger IFN response than GBV-B CL-siRNA could only delay the viral replication. Our results suggest the feasibility of systemic administration of CL-siRNA as an antiviral strategy.     

RNA interference for antiviral therapy

Silencing gene expression through a process known as RNA interference (RNAi) has been known in the plant world for many years. In recent years, knowledge of the prevalence of RNAi and the mechanism of gene silencing through RNAi has started to unfold. It is now believed that RNAi serves in part as an innate response against invading viral pathogens and, indeed, counter silencing mechanisms aimed at neutralizing RNAi have been found in various viral pathogens. During the past few years, it has been demonstrated that RNAi, induced by specifically designed double-stranded RNA (dsRNA) molecules, can silence gene expression of human viral pathogens both in acute and chronic viral infections. Furthermore, it is now apparent that in in vitro and in some in vivo models, the prospects for this technology in developing therapeutic applications are robust. However, many key questions and obstacles in the translation of RNAi into a potential therapeutic platform still remain, including the specificity and longevity of the silencing effect, and, most importantly, the delivery of the dsRNA that induces the system. It is expected that for the specific examples in which the delivery issue could be circumvented or resolved, RNAi may hold promise for the development of gene-specific therapeutics.     

RNA干扰技术在几项研究领域的应用

作为一项新的反向遗传学技术 ,RNA干扰技术正在越来越多地应用于包括鉴定基因功能、疾病治疗、植物病毒抗性研究在内的多项研究领域。在鉴定基因功能研究中 ,由于该技术的操作简便性 ,使得在基因组水平进行大范围的基因功能鉴定成为可能 ;而针对致病相关基因、致病病毒基因组进行RNA干扰 ,可以有效抑制病情恶化 ,有可能成为未来疾病治疗的重要手段 ;同时 ,将RNA干扰技术应用于植物抗病毒研究 ,为工程化植物抗病毒遗传育种提供了一个高效、特异的抗性获得手段。对RNA干扰技术在上述三个研究领域的应用作简要综述 ,并对应用过程中需注意的问题进行了探讨 。